A flash memory uses the flash technology to achieve storage of electronic information. The flash memory has many advantages such as driverless, fast speed, small size, desired compatibility, and large capacity, etc., and, therefore, has been widely used. The flash memory can perform read and write, erase and copy operations on data. Different operations have different drive circuits.
In the flash memory, the data is stored in two forms, ‘1’ and ‘0’, which correspond to two basic memory cells, an erase cell and a program cell, respectively. When the data in the flash memory is read, the type of the memory cell first needs to be determined, whether it is the program cell or the erase cell. When determining the type of the memory cell, a sense amplifier (SA) circuit needs to be used. An array formed by the sense amplifier circuits is usually referred to as a sense array. When the sense amplifier circuit reads the data in the flash memory, a reference signal needs to be used. By comparing the reference signal and a signal outputted from the memory cell, the type of the memory cell can be determined. Therefore, the reference signal is important for the accuracy of a reading result.
The reference signal is generated by a reference circuit. The design of the reference circuit directly impacts the output of the reference signal, and impacts the accuracy of the reading result. However, for existing flash memory, errors may easily occur in the reading result of the flash memory. The disclosed device structures and methods are directed to solve one or more problems set forth above and other problems.